package main

import "fmt"

func main() {
	var width float64 = 12
	var height float64 = 14
	defer func() {
		err := recover()
		if err != nil {
			fmt.Println(err)
		}
	}()

	if width < 0 || height < 0 {
		panic("数值应为正数")
	}
	fmt.Println("面积为", width*height)
}
